This invention relates to an improved cutter bar type harvesting platform for a combine or the like.
Cutter bar type platforms are conventionally carried in front of self-propelled machines, such as combines, and are transversely elongated relative to the direction of travel. The platform is also conventionally vertically adjustable, and, when the platform is being used to harvest such crops as soybeans or the like, the platform is operated as close to the ground as possible. Such platforms conventionally include a floor with a transverse cutter bar along the leading edge of the floor. A reel is also normally provided above the cutter bar and moves the crop toward the cutter bar as the machine advances, the cutter bar serving the crop from the ground. The material leaving the cutter bar is fed to a transverse auger immediately above the floor, and the auger converges the crop along the floor toward the center of the platform, for its rearward discharge. Normally the cutter bar is rigidly attached to the forward end of the platform floor, although it is known to provide flexible type cutter bars, which flex vertically relative to the floor so that the cutter bar follows the contour of the ground.
The tilt of the cutter bar and in the forward portion of the floor, or the angle that the cutter bar and the floor make with the ground about a horizontal transverse axis, is of importance for the proper feeding of the crop to the auger. Also, skids are conventionally provided along the bottom of the platform, and the tilt angle of the skids is also important. However, modern combines are conventionally provided with a wide range of tire sizes and types to accommodate different types of field conditions and the desires of different purchasers. The tire size, of course, affects the height of the combine, which, in turn affects the tilt angle of the platform, and it has been found that when the platform is designed for optimum tilt angle for one size of tire, the tilt angle is substantially less than optimum for different sizes of tires.
It has also been discovered that the distance between the cutter bar and the auger for optimum feeding characteristics varies with different crops and crop conditions. Also, different types of reels are used for feeding different crops to the cutter bar, and adjustments are also conventionally provided to provide for different positions of their reel relative to the cutter bar. Again, the optimum position of the cutter bar relative to the auger varies with the type of reel and reel position. For example, when the platform is harvesting soybeans or dry, easy to feed crops, or grain crops where the straw is long and dry, or when a bat type reel is used, the platform performs better when the cutter bar is a substantial distance in front of the auger, so that the reel sweeps the cutter bar and the crop lays down on the platform floor in front of the auger, the crop feeding more evenly than if the crop were engaged by the auger immediately upon leaving the cutter bar. On the other hand, in wet crops, such as rice, or in down crops, and when pick-up type reel is being used, the platform performs better if the cutter bar is relatively close to the auger, so that the reel positively feed the crop to the auger.